It manages and controls the database in a unified way to ensure the security and integrity of the database. Users access the data in the database through DBMS, and database administrators also maintain the database through DBMS. It can support multiple applications and users to establish, modify and query databases in different ways at the same time or at different times.
Database research spans three fields: computer application, system software and theory. Among them, application promotes the research and development of new systems, and new systems bring new theoretical research, which plays a guiding role in the first two fields. The appearance of database system is a milestone in computer application, which makes computer application change from scientific calculation to data processing, thus making computers widely used in all walks of life and even families.
Although the previous file system can also handle persistent data, the file system does not provide fast access to any part of the data, which is very important for applications with increasing data volume. In order to realize fast access to any part of data, many optimization techniques must be studied. These optimization techniques are often complicated and difficult for ordinary users to realize, so they are completed by system software (database management system).
Extended data
A database system usually consists of four parts:
(1) Database (DB) refers to an organized and accessible collection of data stored in a computer for a long time. The data in the database is organized, described and stored according to a certain mathematical model, which has less redundancy, higher data independence and easy expansibility and can be enjoyed by all kinds of users.
(2) Hardware: all kinds of physical devices that make up a computer system, including external devices needed for storage. Hardware configuration should meet the needs of the whole database system.
(3) Software: including operating system, database management system and application programs. Database management system is the core software of database system. With the support of operating system, it solves how to organize and store data scientifically and how to obtain and maintain data efficiently. Its main functions include: data definition function, data operation function, database operation management and database establishment and maintenance.
(4) Personnel: There are four main categories. The first category is system analysts and database designers. System analysts are responsible for the requirements analysis and specification of application systems. They work with users and database administrators to determine the hardware configuration of the system and participate in the overall design of the database system. The database designer is responsible for determining the data in the database and designing all levels of database schema. The second category is application programmers, who are responsible for writing applications that use databases.